This invention relates to microelectronics packaging technology and, more specifically, to the provision of an enclosure for microelectronics power circuits having high current feedthroughs and to a method for making same.
In the field of microelectronics packaging technology, present practice is to utilize feedthroughs comprising Kovar pins sealed with glass in a Kovar ring frame. The poor thermal conductivity of the glass coupled with the poor thermal and electrical conductivity of the Kovar leads to excessive heating of the feedthroughs when conducting high current. As a result, the current carrying capacity of currently used packages are limited to about five amperes continuous current per package feedthrough due to heating thereof, although forty amperes is acceptable for intermitent current flow at a low duty cycle.
It is therefore objective of this invention to increase the current carrying capability of package feedthroughs by eliminating glass-to-metal seals. Another objective of the present invention is the provision of a power package in which high currents can be routed through the package wall. Yet another objective is to provide tabs that can be evenly spaced along the inner and outer perimeter of the package to allow bussing of current to any point along the walls. A stil further objective is to utilize package walls for current routing to allow increased circuit density. A further objective is to employ feedthroughs along the outer perimeter of the package that act as fins to increase thermal dissipation from the conductors. Yet another objective is to provide feedthroughs having high thermal conductivity and a large contact area to cool the feedthroughs and overcome the above-identified problems with conventional glass feedthroughs.